Abstract

Aims

To assess whether vitamin D levels at birth were associated with risk of having type 1 diabetes up to 10 years of age and the potential modifier effect of ethnic group.

Methods

The Piedmont Diabetes Registry and the Newborn Screening Regional data were linked to identify cases (n = 67 incident children aged ≤10 years at diabetes onset, 2002–2012) and up to five controls (n = 236) matched for birthday and ethnic group. Cards with neonatal blood spot were used and 25-hydroxyvitamin D(3) assessed with tandem mass spectroscopy.

Results

In conditional logistic regression, OR for unit increment of log vitamin D was 0.78 (95 % CI 0.56–1.10). Vitamin D was significantly lower in migrant than in Italian control newborn babies (p < 0.0001), and interaction between vitamin D and migrant status was statistically significant (p = 0.04). Compared to migrant newborns babies with vitamin D ≥ 2.14 ng/ml, migrants with lower levels had an OR of 14.02 (1.76–111.70), whereas no association was evident in Italians.

Conclusions

Our case–control study within the Piedmont Diabetes Registry showed no association between vitamin D levels at birth and risk of having type 1 diabetes up to 10 years of age, apart from the subgroup of migrant babies, which might have clinical implications if confirmed.

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Acknowledgments

This study was supported by DeAgostini Foundation. Novara, Italy. Grant Number 2012 and by University of Turin, ex 60 %. Guarantors of the study are Francesco Cadario and Giovanni Bona.

Conflict of interest

The authors declare that they have no conflict of interest.

Human and animal rights

All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1975, as revised in 2008 [5].

Informed consent

Informed consent of patients included in the study was obtained by the Piedmont Diabetes Registry and the Newborn Screening Regional Center. The study was reviewed and approved by the Ethics Committee of the S. Giovanni Battista Hospital, Turin.